Build and run the self-test, which needs no Xcode project and touches nothing on the system:
swift build -c release
"$(swift build -c release --show-bin-path)/removemacai" selftestBuild the app with tools/build-app.sh, which puts RemoveMacAI.app in .build. A debug build can render every page to PNG without screen-recording permission:
swift build && REMOVEMACAI_SNAPSHOTS=/tmp/shots .build/debug/removemacai appA new tweak goes in Sources/removemacai/Tweaks.swift. Check that macOS still reads its key before adding it, and say how you checked.
Translations live in Localization/<language>.lproj: Localizable.strings keyed by the English text in the code, and Localizable.stringsdict for counts. tools/build-app.sh copies them into the app. tools/check-localization.py <language> lists window text that has no translation yet; run it after changing any text the app shows.
Good first issues: please take one at a time so more people get a turn. Once your PR is merged you're welcome to pick up another.
Every change RemoveMacAI makes is shown before it happens and can be undone, and a new tweak has to keep that. A tweak that can break something people rely on stays out of the presets.
Keep one change per pull request, and say which macOS version and build you tested on. For a bug, the output of removemacai status and sw_vers helps most.